Many gamblers are placing bets on this fighter since its more reliable than you against the casino games, this is all about agility and skills, but the possibility of intent loss to make more money is also possible in this game, what's your take on this?
The movie scenario you mentioned is a product of fiction and might not likely be happening in reality. Since you referred to that UFC fighter as a reliable bet, it means the said fighter might be popular, therefore we can consider him as a big professional fighter.
If these professional players/athletes are involved in intentional loss, the cost of it is so huge, better than being a one-time millionaire just to win the high odds on the bookies. A player might faced sanction such as stripping the status of being a professional athlete with a lifetime ban on that sport, lose sponsorships, face a lawsuit, and many other worse things.
I doubt a professional fighter will be involved in that.